1. Technical Field
Various embodiments of the present invention relate to an electronic device, and more specifically, to a chip tester and a test method of a semiconductor memory device.
2. Related Art
With the explosive increase in use of mobile information devices, such as smartphones and tablet personal computers, using semiconductor memory devices (especially, non-volatile memory devices) as storage media, there is growing interest in the semiconductor memory devices.
In addition, the advancement of various applications has led to an ever-increasing need for highly performing, highly reliable semiconductor memory devices.
A semiconductor memory device is a memory device embodied using a semiconductor, such as silicon (Si), germanium (Ge), gallium arsenide (GaAs), and indium phosphide (InP). Semiconductor memory devices may be broadly classified into volatile memory devices and non-volatile memory devices. A volatile memory device may lose stored data when power is not supplied. Volatile memory devices may include a static random access memory (SRAM), a dynamic RAM (DRAM), and a synchronous DRAM (SDRAM). A non-volatile memory device may retain stored data even when power is not supplied. Non-volatile memory devices may include a read-only memory (ROM), a programmable ROM (PROM), an electrically programmable ROM (EPROM), an electrically erasable and programmable ROM (EEPROM), a flash memory device, a phase-change RAM (PRAM), a magnetic RAM (MRAM), a resistive RAM (RRAM), and a ferroelectric RAM (FRAM). Flash memory devices may be divided into a NOR type flash memory and a NAND type flash memory.
In general, a non-volatile memory device includes a plurality of memory blocks. Defective blocks may be generated in some of the memory blocks due to fabrication process errors. When the defective blocks takes up a predetermined percentage or less, the corresponding non-volatile memory device may be designated as a normal memory device.
Meanwhile, there may be memory blocks that are not allowed to include defective blocks due to customers' request.
In the following description, such memory blocks are referred to as guarantee blocks. When defective blocks occur in the guarantee blocks, the corresponding non-volatile memory device may be designated as an abnormal memory device. As a result, the fabrication yield of non-volatile memory device may decrease.